The present invention relates to the manufacture of high-alloyed steel particularly steel having a relatively high content in those kinds of elements that are deemed to have a high affinity to oxygen such as Cr, Mn, under utilization of a basic, oxygen blowing converter.
It is known that during the manufacture of steel and under use of oxygen the accompanying and alloying elements of the iron produce a certain amount of slag, particularly during decarbonization and dephosphorization, and that slag production is high if these elements have a higher affinity to oxygen than the corresponding affinity of iron itself.
The manufacture of high-alloyed steel particularly of steel with a high content in Cr and Mn, therefore, cannot be manufactured in an oxygen blowing converter in an economic fashion since the loss in alloying elements is significantly high. For example, steel with an intended Cr content in excess of 3% or an intended Mn content in excess of 2% are preferably made either in an electric furnace or in an. AOD converter.
On the other hand, it has become known through German printed patent application No. 19 53 888 or No. 22 53 480 to manufacture Cr-steel under utilization of oxygen in general. However, in order to cope with the activity of the oxygen it is necessary to dilute the oxygen or to maintain the decarbonization process at a particular (low) speed. Equipment meeting these requirements is complex and expensive. This procedure requires supervision and extensive control of the decarbonization process and is accompanied by a commensurate change in the inert gas content that has been (or is) mixed with the oxygen. The productivity of such an equipment is not very high owing to the intentional delay in the process introduced for reasons mentioned above.